Rotary arcual sample for particulate materials

ABSTRACT

A rotary arcual sampler for sampling streams of particulate material having a housing with upper and lower openings vertically aligned intermediate of the housing wall and vertical central axis, an internal sample chute rotatable about the central axis having an upper opening and a lower opening through the vertical central axis, a pair of cutter lips disposed near opposite sides of the upper chute opening, said cutter lips extending radially from the vertical central axis and having a surface inclined slightly from the vertical.

Apr. 17, 1973 2,729,547 1/1956 Alleman R ROTARY ARCUAL SAMPLE FOR PARTICULATE MATERIALS [75] inventor: Fred R. Huntington, Salt Lake City, Primary Emmi'ferwEvon Blunk Utah Assistant Exammerl-l. S. Lane Attorney-Wi1liam S. Britt et a1.

[73] Assignee: The Galigher Company, Salt Lake City, Utah ABSTRACT [22] Filed: Feb. 7, 1972 A rotary arcual sampler for sampling streams of particulate material having a housing with upper and Appl. No.: 224,171

lower openings vertically aligned intermediate of the housing wall and vertical central axis, an internal sample chute rotatable about the central axis having an upper opening and a lower opening through the vertical central axis, a pair of cutter lips disposed near opposite sides of the upper chute opening, said cutter lips extending radially from the vertical central axis N] 3 BUB 0 2 3 1 Y 332 N 9 B l 2 2 2 52 us. [51] Int. [58] Field of Search....................

and having a surface inclined slightly from the vertical [56] References Cited UNITED STATES PATENTS 643,102 2/1900 Bates.....,.......................222/3l8 UX 10 Claims, 5 Drawing Figures ROTARY ARCUAL SAMPLE FOR PARTICULATE MATERIALS BACKGROUND OF THE INVENTION Rotary arcual samplers having rotatable chutes have been utilized to collect samples of particulate material from falling streams of particles. One shortcoming of such samplers has been the impingement of the upper portions of the sampler chute with the falling particles, disturbing the particle pattern and altering particle distribution. It is one of the objectives of this invention to provide a rotary arcual sampler with cutter lips which interfere very little with falling particles collected in the sampler chute.

OBJECTS OF THE INVENTION A primary objective of this invention is to provide a rotary arcual sampler with radially extending cutter lips inclined slightly from the vertical so as to disturb to a minimum the falling particles.

Another object of this invention is to provide a rotary arcual sampler with horizontally adjustable lips to provide means for regulating the size of the opening offered to the falling stream of particles.

A further object of this invention is to provide a rotary arcual sampler with vertically adjustable cutter lips to provide flexibility in sampling streams of various particle sizes.

A further object of this invention is to provide a rotary arcual sampler with a minimum of moving parts to I enhance reliability and reduce maintenance.

DESCRIPTION OF INVENTION A rotary arcual sampler for sampling a stream of particulate material, said sampler having horizontally adjustable, inclined cutter lips has now been invented. A rotatable sampler chute extending radially from the central vertical axis isembodied within an outer housing. Particulate material is received in the open top of said chute when it rotates through a stream of particulate material descending through the sampler housing.

Collected particulate material is discharged at the base of the sample chute into a rotatable vertical barrel disposed along the central vertical axis.

Further description of the invention may be facilitated by reference to the following figures.

FIG. 1 is a perspective view of a rotary arcual sampler with the interior exposed.

FIG. 2 is a plan view of the rotatable sampler chute.

FIG. 3 is an elevational view of the inclined cutter Ii s.

FIG. 4 is a fragmented elevational view of the cutter lips attached to the central shaft.

FIG. 5 is a fragmented perspective view of vertically adjustable cutter lips.

The sampler illustrated in FIG. 1 has an upper body 10 of sufficient inside dimensions to permit rotation of sample chute 11 about the central vertical axis of the sampler. The sample chute 11 has a sloped forward edge 12 and a rear edge coextensive vertically with a hollow barrel 13. The hollow barrel 13 has an opening in the sidewall near the base of the sample chute to receive particulate material from the sample chute. Particulate material received in barrel 13 is discharged from the sample discharge pipe 14.

The hollow barrel I3 is driven by shaft 15 which passes through bearing 16 located centrally in the top cover 10a of the sampler. Motor 17 drives shaft 15. The motor may be connected directly to shaft 15 or connected intermediately to the shaft by a gear reducer or belt drive. The hollow barrel 13, attached at its upper terminus to shaft 15, extends downward into the larger diameter discharge pipe 14. The collar 18 is fixed to the lower terminus of barrel 13. Collar 18, an inverted cup, has an inside diameter slightly larger than the outside diameter of pipe 14 and rotates on an annular bearing surface (not shown) at the top of pipe 14.

The bottom portion of the sampler body has a decreasing cross-sectional area, tapering to the reject opening 19. The reject opening is preferably in vertical alignment, i.e., in register, with material inlet opening 20 at the top of the sampler. Thee sampler chute 11 extends a sufficient distance radially from barrel 13 to pass under opening 20 during rotation of the chute.

The size of the upper opening of the sampler chute is controlled by a pair of cutter lips 21 and 22, as illustrated by FIGS. 2 and-3. The cutter lips illustrated are angle members each having a rectangular, horizontal flat member 23 and 24, which when abutting one another, closes the upper opening of the sample chute. Vertical blades 25 and 26 are elongated rectangular members which incline slightly from the vertical generally from about 3 to about 20 and preferably from about 5 to about 10 with an optimum fixed angle of about 8".

The cutter lip blades are inclined in the direction of rotationso that the upper, leading edge of the blade enters the particle stream first.

Each cutter lip. is attached at one end to a ring member 27 and 28 which fits over shaft 15. The rings are clamped to shaft 15' by set screws 29 and 30. The cutter lips, when open, form a sector of a circle. A horizontal opening formed by the cutter lips adjustable from 0 to about 30 is generally sufficient to accommodate theupper opening of the sample chute 11. Regulating the size of the chute opening determines the quantity of sample collected for a given rotational speed.

In operation the sampler chute is rotated about the central vertical axis of the sampler. The speed of rotation may be varied, for example, through use of a rheostat or variable resistor placed in the power supply to motor 17 or through a variable gear reducer or variable-pulley, belt drive system. It is generally preferred to have a fixed rotational speed and vary other factors such as the chute opening. Also, the rotation of the sample chute may be periodic. A timer or other device may regulate the duration of the period during which power is supplied to motor 17. Either system provides a method of regulating the number of revolutions per unit time traveled by sample chute 11. The desirability of regulating the sampler chute rotational speed is explained hereinafter.

The sampler chute '11 is always rotated in the same direction in order -to take advantage of the inclination of the cutter lips.

The sampler chute may be rotated continuously at a predetermined rotational speed, matched to the inclination of the cutter lips. Also, the chute may be rotated periodically by the inclusion of a timer and a limit switch in the system. For example, a sample may be desired only once every 10 minutes. A timer set to supply current for a few moments every 10 minutes is placed in the electrical supply line to the coil of a main relay switch which controls current flow to the motor and to its own coil so that the switch remains closed after actuation by the timer relay even though the timer relay opens before the sampler chute has completed one revolution. A limit switch having a mechanical contact actuated by the sampler chute each time it passes said limit switch is provided to open a relay switch in the supply line from the main switch to the coil of the main switch.'A momentary loss of power to the coil of the main switch allows it to open, thereby removing current from the motor and placing an open switch in the current supply to its own coil. Thus, the main switch remains open until again actuated by the timer relay switch even though the limit relay switch closes momentarily after being opened. With the limit relay switch in a closed position, the system is ready for another cycle upon actuation of the timer relay switch by the timer.

Through the use of a timer-limit switch circuit of the type described, as a comparable timer circuit, including a timer circuit which operates periodically for a time sufficient for the chute to make one revolution, a predetermined volume or weight of sample material, or number of samples, can be collected hourly without disturbing the rotational speed of the chute. The sampler, of course, can be operated by a manual switch whereby an operator selects the period between samples and determines the number of revolutions permitted during a single sampling operation.

The optimum rotational velocity is determined by several factors: (I) The angle of inclination of the cutter lips; and (2) The velocity of a freely falling particle. Observations with falling particles of various typesindicate an assumed velocity of about l5ft./sec. is an acceptable average for the variety of materials, particle size and height of fall usually encountered in typical sampling situations. The cutter lip angle is preferably about 5 to about from the vertical although greater angles, for example, up to about may be provided for samplers having higher rotational velocities.

It is, of course, a primary objective of the invention to extract a sample from a falling stream of particles while disturbing the stream the least. By rotating the chute at a speed matched to the inclination of the cutter lips the particles entering the chute are disturbed very little and do not contact the upper portion of the chute. The least contact possible with the chute is desired to prevent, among other things, attrition, which gives a false reading of particle size distribution.

The inclination of the cutter lips may be fixed during fabrication of the unit, or vertically adjustable cutter lips may be provided. Vertically adjustable cutter lips are readily constructed by placing hinge means along 'the bottom junction of the cutter lips member and horizontal member 23 (FIG. 3). An extension of face 31 above the cutter lips having a flared surface to a greater horizontal-dimension than the chutes, provides a member for adjustably attaching the cutter lips by screw or pin means placed through holesin member 31a. A fragmentary view of such an arrangement (FIG. 5) illustrates the face extension 31a, vertical cutter blades 25 and 26 and hinge means 32.

Varying the inclination of thee cutter blades requires adjustment of the rotational speed of the sample chute. This may be accomplished by interconnecting the drive motor to the shaft 15 by belt means and replacing the sheaves with larger or small sheaves to change the drive ratio as desired. Increasing the inclination of the cutter blades from the vertical requires an increase in rotational speed. For example, increasing cutter lip inclination from about 5 to about 10 should preferably be accompanied by an increase in rotational speed of about two fold.

The discharge from sample discharge pipe 14 may be directed to a rotary sample collector of the type described in copending application Ser. No. 123,996, wherein periodic samples are separately collected and identified.

The instant invention has a wide variety of applications, however, it is particularly useful in sampling bulk materials having a particle size of about three-quarter inch down to microscopic size. The particle size range may vary very little or vary over the entire range.

In adjusting the opening between cutter lips it is preferred to have the minimum spacing therebetween at least about three times the diameter of the largest particle being sampled. Thee possibility of bridging is substantially eliminated when such a spacing isprovided. The minimum spacing is provided between cutter lips under opening 20 at the point closest to the central vertical axis which is in substantial vertical alignment with the portion of inlet opening 20 closest to the central vertical axis. Assuming, for example, in a .particular construction that point to be about one-half the horizontal length of the cutter lips, for a maximum particle diameter of three-fourths inch, the opening at that point would be 2 A inches while the spacing between the outer ends of the cutter lips would be about 4 k inches.

Although the cutter lips may be provided with an angular adjustment, see FIG. 5, it is generally not necessary to do so. An angular inclination of about 5 to 10 and particularly about 8 for a sampler operated at about 20 rpm satisfactorily collects particles sized from three-quarter inch down to microscopic size. An average particle velocity of about 15 feet/sec. is attained for most types of particles falling through a distance of about 3 feet. If a particle size or density results in a substantially different particle velocity through the sampler, then the height of fall can be shortened or lengthened so that the assumed particle velocity is achieved through the sampler. The sampler location can be raised or lowered to provide the correct falling distance for any mineral particle of less than about three-fourths inch to achieve a particle velocity of about 15 ft/sec. through the sampler.

A fixed rotational velocity of about 20 rpm provides provide the right height of fall to attain the assumed velocity.

Although the invention has been described by reference to specific embodiments thereof, it is not limited solely thereto, but includes all the variations and modifications falling within the scope of the appended claims.

I claim:

1. A rotary arcual sampler for sampling a falling stream of particulate material comprising a. a sampler body having an upper inlet opening for particulate material and a lower discharge opening disposed in substantial vertical alignment with said upper opening;

b. a sample chute rotatable about a central vertical axis, said chute having an upper opening offset from the vertical axis, and a lower axial discharge opening, said upper opening of the sample chute rotatably alignable with the upper inlet opening of said sampler body;

c. a pair of cutter lips disposed along the upper opening of said chute, said cutter lips inclined a few degrees from the vertical and being adjustable to regulate the size of the upper opening of the sample chute.

2. The sampler of claim 1 wherein each cutter lip is an elongated member extending from the central vertical axis of the sampler, said cutter lip having a substantially vertical element and a substantially horizontally element.

3. The sampler of claim 1 wherein the chute opening formed by the cutter lips is a sector ofa circle.

4. The sampler of claim 1 wherein the vertical ele ment of each cutter lip is inclined in the same direction and substantially parallel to the other.

5. The samppler of claim 1 wherein the vertical element of each cutter lip is inclined about 5 from the vertical.

6. The sampler of claim 1 wherein said sample chute is connected by a central drive shaft to drive means capable of rotating said chute at a rotational speed of about 10 rpm to about rpm.

7. The sampler of claim 2 wherein the vertical element of said cutter lips is angularly adjustable.

8. The sampler of claim 1 wherein said sample chute is connected to electrically powered drive means having a timing system operatively connected to the drive means to energize same periodically.

9. The sampler of claim 2 wherein each cutter lip member is attached to a central drive shaft by ring means.

10. The sampler of claim 1 wherein the lower axial discharge opening of said sample chute is a hollow vertical barrel disposed along the central vertical axis, said barrel connected at its upper terminus to a central drive shaft. 

1. A rotary arcual sampler for sampling a falling stream of particulate material comprising a. a sampler body having an upper inlet opening for particulate material and a lower discharge opening disposed in substantial vertical alignment with said upper opening; b. a sample chute rotatable about a central vertical axis, said chute having an upper opening offset from the vertical axis, and a lower axial discharge opening, said upper opening of the sample chute rotatably alignable with the upper inlet opening of said sampler body; c. a pair of cutter lips disposed along the upper opening of said chute, said cutter lips inclined a few degrees from the vertical and being adjustable to regulate the size of the upper opening of the sample chute.
 2. The sampler of claim 1 wherein each cutter lip is an elongated member extending from the central vertical axis of the sampler, said cutter lip having a substantially vertical element and a substantially horizontal element.
 3. The sampler of claim 1 wherein the chute opening formed by the cutter lips is a sector of a circle.
 4. The sampler of claim 1 wherein the veRtical element of each cutter lip is inclined in the same direction and substantially parallel to the other.
 5. The sampler of claim 1 wherein the vertical element of each cutter lip is inclined about 5* from the vertical.
 6. The sampler of claim 1 wherein said sample chute is connected by a central drive shaft to drive means capable of rotating said chute at a rotational speed of about 10 rpm to about 40 rpm.
 7. The sampler of claim 2 wherein the vertical element of said cutter lips is angularly adjustable.
 8. The sampler of claim 1 wherein said sample chute is connected to electrically powered drive means having a timing system operatively connected to the drive means to energize same periodically.
 9. The sampler of claim 2 wherein each cutter lip member is attached to a central drive shaft by ring means.
 10. The sampler of claim 1 wherein the lower axial discharge opening of said sample chute is a hollow vertical barrel disposed along the central vertical axis, said barrel connected at its upper terminus to a central drive shaft. 